BIODEGRADATION OF AZO DYE BY ADAPTED MIXED MICROBIAL CULTURES

Wastewater effluents from azo dye production and other dye-stuff using industries contain significant amounts of highly resistant azo dyes that require special treatment processes to prevent groundwater contamination. The present study is based on the approach of aerobic followed by anaerobic step for biodegradation and decolorization of azo dye. The main objective of this work was the adaptation, isolation and preparation of mixed microbial culture, from laboratory collection, catabolically able to biodegrade under aerobic conditions bordo azo dye present in mother lye after industrial production of that dye. The anaerobic step needed for biodegradation of azo dye was performed by the use of adapted active anaerobic sludge from a wastewater treatment plant of the sugar industry. The adapted aerobic and anaerobic microbial cultures demonstrated significant biodegradative enzymatic potential and can be further used for development of a continuous aerobic – anaerobic process for the treatment of wastewater from industrial production of azo dye

Azo Dyes, Their Environmental Effects, and Defining a Strategy for Their Biodegradation and Detoxification

Intenzivan industrijski razvoj popraćen je sve većom kompleksnošću sastava otpadnih voda, što u smislu učinkovite zaštite okoliša i održivog razvoja nalaže potrebu pospješivanja kvalitete postojećih te uvođenjem novih postupaka obrade otpadnih voda, kao iznimno važnog čimbenika u interakciji čovjeka i okoliša. Posebnu znanstveno-tehnološku pozornost zahtijevaju novosintetizirani ksenobiotici, poput azo-boja, koji su u prirodi veoma teško razgradivi. Azo-boje podložne su bioakumulaciji, a zbog alergijskih, kancerogenih, mutagenih i teratogenih svojstava nerijetko su prijetnja zdravlju ljudi i očuvanju okoliša. Primjenu fi zikalnokemijskih metoda za uklanjanje azo-boja iz otpadnih voda često ograničavaju visoke cijene, potrebe za odlaganjem nastalog štetnog mulja ili nastanak toksičnih sastojaka razgradnje. Biotehnološki postupci su, zbog mogućnosti ekonomične provedbe i postizanja potpune biorazgradnje, a time i detoksifi kacije, sve zastupljeniji u obradi svih vrsta otpadnih voda, pa tako i onih koje sadržavaju azo-boje.Intense industrial development has been accompanied by the production of wastewaters of very complex content, which pose a serious hazard to the environment, put at risk sustainable development, and call for new treatment technologies that would more effectively address the issue. One particular challenge in terms of science and technology is how to biodegrade xenobiotics such as azo dyes, which practically do not degrade under natural environmental conditions. These compounds tend to bioaccumulate in the environment, and have allergenic, carcinogenic, mutagenic, and teratogenic properties for humans. Removal of azo dyes from effl uents is mostly based on physical-chemical methods. These methods are often very costly and limited, as they accumulate concentrated sludge, which also poses a significant secondary disposal problem, or produce toxic end-products. Biotechnological approach may offer alternative, lowcost biological treatment systems that can completely biodegrade and detoxify even the hard-to-biodegrade azo dyes